#include <iostream>         //input output starem
using namespace std;       //使用命名空间
//等效 #include <stdio.h>


int main(int argc,char*argv[])
{
    float x=0,y=0;
    char ch='\0';
    cout<<"please input :"<<endl;
    cin>>x>>ch>>y;
    if('+'==ch)
    {
        cout<<"x+y="<<x+y<<endl;
    }
    else if ('-'==ch)
    {
        cout<<"x-y="<<x-y<<endl;
    }
    else if ('*'==ch)
    {
        cout<<"x*y="<<x*y<<endl;
    }
    else if ('/'==ch)
    {
        cout<<"x/y="<<x/y<<endl;
    }
    else
    {
        cout<<"error"<<endl;
    }
    
    
    //cout<<"hello world"<<endl;
    return 0;
}